M. A. M. Uosif

Gamma radioactivity measurements in Nile River sediment samples

River sediment depositions on the bottom of rivers most frequently consist of sand and gravel particles with dierent grain sizes, which make them particularly valuable for building construction. Knowledge of the radioactivity present in building materials enables one to assess any possible radiological hazard to humankind by the use of such materials. A total of 69 Nile River sediment samples from 8 cities and 24 locations were collected along a 139-km area in Minia, Egypt. The radiological hazards were calculated for the investigated area. The results of the study could serve as important baseline radiometric data for future epidemiological studies and monitoring initiatives in the study area.

Natural radioactivity levels and radiological hazards indices of chemical fertilizers commonly used in Upper Egypt

Abstract In order to determine the radiological hazards indices of chemical fertilizers commonly used in Upper Egypt, The concentrations of natural radionuclides 226Ra, 232Th and 40K in seven types of chemical fertilizers used in Upper Egypt have been measured by gamma spectrometry using NaI (Tl) 3″×3″ detector. The ranges of concentration levels of 226Ra, 232Th and 40K were 12±0.6–244±12.6, 3±0.2–99±4.9, and 109±5.5–670±34Bqkg−1, respectively. In the other side, the range values obtained from fertilizer samples under investigation were (33.1–392.3Bqkg−1), (0.6–2.7), (15.6–177.8nGyh−1) and (20.1–229.1μSvy−1) for radium equivalent activity, γ-radiation hazard index Iγr, Dose rate (nGyh−1) and annual effective dose equivalent (AED) in the air to the occupational workers, respectively. The obtained values were compared with available reported data from other countries in literature.

Seasonal behavior of radon decay products in indoor air and resulting radiation dose to human respiratory tract

Abstract Most of radiation hazard of indoor radon is largely due to the radon progenies, which are inhaled and deposited in the human respiratory tract. It is essential to evaluate aerodynamic characteristics of the radon progenies, which are either attached or unattached to aerosol particles, because the dose is strongly dependent on the location of deposition in respiratory tract and hence on the aerodynamic characteristics of the aerosol particles. This paper presents the seasonal behavior of radon decay products in indoor air under domestic conditions at Nagoya University, Japan. A low pressure cascade impactor as an instrument for classifying aerosol sizes and imaging plate as a radiation detector have been employed to characterize the activity size distribution of short-lived radon decay products. In parallel, radon and its progenies concentrations were measured. Taking into account the progeny characteristics, the inhalation dose in the different seasons was also estimated based on a lung dose model with the structure that is related to the ICRP66 respiratory tract model. The result evident that, the highest dose 0.22 mSvy−1 was observed during the winter where the highest value of equilibrium equivalent concentration of radon (EEC) and lowest value of the activity median aerodynamic diameter (AMAD) were found in this season; whereas, the dose in spring appeared to be lowest 0.02 mSvy−1.

Measurement of natural radioactivity in granites and its quartz-bearing gold at El-Fawakhir area (Central Eastern Desert), Egypt

Abstract The distribution of natural radionuclides (226Ra, 232Th and 40K) in Granites and its quartz-bearing gold at El-Fawakhir area (Central Eastern Desert, Egypt) were measured by using γ-ray spectroscopy [NaI (Tl) 3″×3″]. X-Ray Fluorescence technique was used for chemical analyses of the studied samples. The specific activity of 226Ra, 232Th and 40K values are in range (3±0.5 to 43±2Bqkg−1), (5±0.7 to 41±2Bqkg−1) and (128±6 to 682±35Bqkg−1) respectively. The absorbed dose rates ranged from 13.8 to 58.4nGyh−1, where the total effective dose rates were determined to be between 16.7 and 70.9μSvy−1. The maximum external hazard index (Hex) is 0.3nGyh−1. The calculated values of the excess lifetime cancer risks (ELCR) and annual effective dose rate values are in between (8.48×10−5 and 2.63×10−4) and (24.2 and 72.9μSvy−1) respectively. Geochemically, the studied granites consist of major oxides, they are characterized by SiO2, K2O, Na2O, Al2O3, and depleted in CaO, MgO, TiO2, and P2O5. The average absorbed dose rate (Do) in air is 37.8nGyh−1 for the whole studied samples, this value is about 3.78% of the 1.0mSvy−1 recommended by (ICRP-60,1991) to the public, so there is no radiological risk for the workers in that area.