Assessment of Radon, Radium, and Uranium Concentrations in Decorative Materials (Used to walls) Samples in Iraqi Markets

In present study, natural alpha emitters (222Rn, 226Ra, and 238U) were tested in decorative materials used as walls collected from different Iraqi local markets by CR-39 detectors that it was purchased from TASTRAK Analysis System. Annual effective dose and radon exhalation rate were calculated. The results obtained showed that the range and average value of 222Rn concentrations in air container were 7.94 – 738.10 Bq/m3 and 252.38±37.63 Bq/m3, while 222Rn concentrations in in sample were 45.73– 4252.99 Bq/m3 and 1454.25±216.84 Bq/m3. The ranged of 226Ra and 238U concentrations were 0.010- 1.000 Bq/kg, with an average value 0.278±0.04 Bq/kg and 0.01- 1.24 ppm, with an average value 0.344±0.05 ppm, respectively. The results obtained showed that the range and average value of annual effective dose in mSv/y were 0.2 –18.62 and 6.29±0.95. Also, it is found that the mass exhalation rate as well as surface exhalation rate were 8.38±1.33 mBq/kg.day and 240.77±36.56 mBq/m2.day, respectively. The data of 222Rn concentration (in air container), and annual effective dose in some samples of the present study were higher than the global limit range (200-300 Bq/m3), and (3-10 mSv/y) according to ICRP. While, all results of 226Ra, and 238U concentrations as well as the mass with surface exhalation rate were within the permissible limits that suggested by UNSEAR, and ICRP. Then, it can be concluded that the most samples of decorative materials which used as walls according to radiation scope no causes health risk.

Natural Radionuclide (Gamma and Alpha Emitters) in Grain Samples Collected from Kerbala Governorate, Iraq

The aim of this research is to detect nature radioactivity for gamma emitters (specific activity 238U, 232Th, and 40K) using NaI(Tl) detectors and alpha emitters (concentrations of 222Rn, 226Ra, and 238U) using CR-39 detectors in selected samples of grain that are collected from Kerbala governorate. Also, annual effective dose and some radiological parameters due to gamma and alpha emitters to assess the health risk were calculated. Results have been shown that the average value of specific activities for 238U, 232Th and 40K were 6.61±0.91 Bq/kg, 3.07±0.22 Bq/kg and 227.59±32.34 Bq/kg respectively, while the average value of alpha emitters concentrations for 222Rn, 226Ra, and 238U were 3.99±1.13 Bq/m3, 4.69±1.28 mBq/kg and 0.072±0.019 Bq/kg respectively. The results of average total of annual effective dose associated with the exposure due to gamma and alpha emitted from ingestion grain samples in the present study were 0.139±0.013 mSv/y and 0.172±0.047 µSv/y, respectively. The results of natural Radionuclide and radiological parameter hazard based on gamma and alpha emitters from grain samples were discovered to be within the world acceptable levels. Finally, natural radioactivity from the grain samples that collected from Kerbala governorate were safety for the human consumption.

The Alpha Particle Doses Received by Students and Staff in Twenty Schools in the North of Hebron Region - Palestine

The aim of the current study was to measure indoor radon concentration levels and its resulting doses received by the students and staff in schools of the directorate of education in the north of Hebron region- Palestine, during the summer months from June to September (2018), using CR-39 detectors. In this study, a total of 567 CR-39-based radon detectors were installed in the selected schools. The average radon concentrations were found to be 90.0, 66.5 and 58.0 Bqm-3 in Halhul, Beit Umar and Alarrub camp schools, respectively. Based on the measured indoor radon data, the overall average effective dose for the studied area was found to be 0.31 mSvy-1. Reported values for radon concentrations and corresponding doses are lower than ICRP recommended limits for workplaces. The results show no significant radiological risk for the pupils and staff in the schools under investigation. Consequently, the health hazards related to radiation are expected to be negligible. Keywords: Radon concentration, Alpha particles, Annual effective dose, Schools. PACs: 29.40.−n.

Indoor radon concentration and a diffusion model in dwellings situated in a subalkaline granitoid area, Southern Brazil

Radon (Rn), a radioactive element, has especial interest in medical geology because long-term exposure to high concentration is related to lung cancer. In this study, outdoor and indoor radon measurements were conducted in dwellings of the Piquiri Syenite Massif, located in southern Brazil, given the relative high Rn content in soils of this region. Measurements were done using CR-39 detectors and placing them inside and outside dwellings. Moreover, a one-dimensional diffusion model was performed in order to quantify the natural transport of Rn to the air in confined and aerated environments. Results indicate that the region presents relatively low air Rn concentrations, within the environmental limits; however, the health risk might increase in confined and ill-ventilated environments because of transfer from soil and exhalation from ornamental rock-material often found inside dwellings. The main north facies of the syenite, where most of the rock extractions are located, was found to have the highest air Rn concentration because of the higher soil Rn concentration, compared to other facies of the syenite.

Effects of Storage Time and Pre-Etching Treatment of CR-39 Detectors on Their Response to Alpha Radiation Exposure

Radon passive monitors based on solid state nuclear track detectors (SSNTD), especially CR-39, are widely used in radon and thoron studies. They may be subjected to the influence of external factors, like changing of temperature, humidity, and pressure, both before and during the measurement. Evaluation of the exposed detectors involves chemical processing, whose conditions also influence the measurement results. The aim of this study was to check several factors, as to whether they may modify the response of CR-39 detector: concerning the phase before evaluation, storage time, and temperature during storage; and concerning the evaluation procedure, etching time, and pre-etching treatment using hot water and carbon dioxide atmosphere. Two experiments were conducted by irradiation of CR-39 detectors using alpha particles emitted from a mono-energetic 241Am source and exposed in radon atmosphere. Track density dependence of the age of production was found to be statistically not significant. On the other hand, pre-etching treatment using hot water and carbon dioxide with different etching times showed statistically significant effects on track area, track sensitivity, and roundness. It was concluded that there are simple methods to increase performance of nuclear track detectors, and that storage time is not a factor of concern.

Residential Indoor Radon Assessment in the Vicinity of some Dumpsites in Lagos, Nigeria

Dumpsites in Nigeria are generally open and significantly elevate the pollution and contamination level of the total environment. Indoor radon was measured with CR-39 detectors in some buildings in the vicinity of dumpsites in Lagos, Nigeria. Eight (8) dumpsites (4 dormant and 4 active dumpsites) were chosen for this study. Detectors were exposed in 50 houses randomly selected within 0 and 100m away from the dumpsites. The detectors were exposed for 3 months. They were then retrieved and etched in a 6M NaOH solution in a water-bath at a temperature of 90o C for 3 hours. Tracks were counted using a semi-automatic system with a DCE camera mounted on a microscope and connected to a PC. Radon concentration ranged from 24.00±4.86 to 656.00±131.20 Bqm-3 in the active dumpsites.Mean concentrations were 120.3±24.0, 257±51.4, 179.8±33.6, and 131.5±19.4, respectively in Oke-Odo, MRF, Olusosun, and Solus-3. In the dormant sites, concentration ranged from 16±3.2 to 931±186.3 Bqm-3 having means of 194.17±38.80, 206.75±41.33, 223.25±44.69, and 334±66.85Bqm-3 , respectively in Oke-Afa, Solus-1, Solus-2, and Solus-4. The annual effective dose and cancer risk in the active and dormant dumpsites were (3.60 mSv, 8.97 per million person-yearly) and (4.53 mSv, 12.47 per million person-yearly), respectively. This study revealed some high value of radon concentrations in some houses close to the dormant dumpsites than in the active dumpsites. This is unsafe and can cause severe health issues in the long term. Keywords: Radon, dumpsites, Olusosun, CR-39, buildings, Lagos state, SOLUS