MODELLING AND SIMULATION FOR RADIOLOGICAL DOSE ASSESSMENT OF PSAMMOTHERAPY AND CLIMATOTHERPY

2020 ◽  
Vol 188 (3) ◽  
pp. 276-284
Author(s):  
Kh A Allam

Abstract Patient and occupational dose rates due to psammotherapy (sand therapy) and climatotherapy treatments in high natural background areas in Egypt have been evaluated. Monte Carlo mathematical simulations using adult human phantoms were applied to consider the effect of elevated 238U, 232Th and 40K concentrations and the nonhomogeneous distribution of natural radionuclides in beach sand. Three situations: phantom covered by sand or lying on the beach and points in air at several heights above sand level, were considered. The gamma-ray doses per treatment were calculated at a reference point located on the phantom surface centrally above the genital area. The thus calculated patient-absorbed-dose ranges at this reference point were 0.006–0.018 mGy and 0.004–0.023 mGy per climatotherapy and psammotherapy treatments, respectively.

Author(s):  
Ajithra A K ◽  
Shanthi G.

<div><p><em>Natural radionuclides of terrestrial origin have very long half – lives or driven from very long – lived parent radionuclides, which have been created in stellar processes before the earth formation. The study of natural radioactivity in marine and coastal environments is of significant importance for better understanding of oceanographic and sedimentological processes. The sampling sites are selected to cover randomly to cover the southern part. The soil samples have been collected in beach sides. In situ gamma measurements were conducted using a high-purity germanium (HPGe) detector (coaxial cylinder of 50.1 mm in diameter and 44 mm in length) with a relative efficiency of 50% and an energy resolution (FWHM) of 1.8 keV at the 1.33 MeV reference transition of <sup>60</sup>Co. The measurements shows that the values of the absorbed dose rates in air in the investigated area are lower than the recommended limit by the United Nations Scientific Committee on the Effect of Atomic Radiation.</em></p></div>


2020 ◽  
Vol 190 (3) ◽  
pp. 324-330
Author(s):  
C K Wanyama ◽  
F W Masinde ◽  
J W Makokha ◽  
S M Matsitsi

Abstract Radiological hazards associated with naturally occurring radionuclides in materials from Rosterman gold mine were assessed by analysis of 30 samples. The gamma-ray spectrometric analysis of tailing samples reported an average activity concentration of 263 ± 13, 123 ± 6 and 84 ± 4 Bq kg−1 for 40K, 232Th and 226Ra, respectively. The average absorbed dose rate was 124 ± 6 nGy h−1, while the annual effective dose of 0.4 ± 0.02 mSv y−1 for indoor and 0.3 ± 0.01 mSv y−1 for outdoor were reported. The mean and range of radiological parameters (external and radium equivalent) calculated from the tailing samples were within the permissible limits and hence mining of gold at Rosterman has no significant radiological health implication on the miners and the surrounding population.


2010 ◽  
Vol 58 (spe4) ◽  
pp. 25-32 ◽  
Author(s):  
Wagner de S. Pereira ◽  
Alphonse Kelecom ◽  
Delcy de A. Py Júnior

A methodology was developed for converting the activity concentration of radionuclides (Bq kg-1) into absorbed dose rate (Gy y-1), aiming an approach to environmental radioprotection based on the concept of standard dose limit. The model considers only the internal absorbed dose rate. This methodology was applied to the cubera snapper fish (Lutjanus cyanopterus, Cuvier, 1828) caught off the coast of Ceará. The natural radionuclides considered were uranium-238, radium-226, lead-210, thorium-232 and radium-228. The absorbed dose rates were calculated for individual radionuclides and the type of emitted radiation. The average dose rate due to these radionuclides was 5.36 µGy y-1, a value six orders of magnitude smaller than the threshold value of absorbed dose rate used in this study (3.65 10³ mGy y-1), and similar to that found in the literature for benthic fish. Ra-226 and U-238 contributed 67% and 22% of the absorbed dose rate, followed by Th-232 with 10%. Ra-228 and Pb-210, in turn, accounted for less than 1% of the absorbed dose rate. This distribution is somewhat different from that reported in the literature, where the Ra-226 accounts for 86% of the absorbed dose rate.


2018 ◽  
Author(s):  
Wen Yu ◽  
Mathew P. Johansen ◽  
Jianhua He ◽  
Wu Men ◽  
Longshan Lin

Abstract. In order to better understand the impact of Fukushima Nuclear Power Plant (NPP) Accident on commercial marine species, squid (Ommastrephe bartrami) samples, obtained from the northwestern Pacific in November 2011, were analyzed for a range of artificial and natural radionuclides (Cs-134, Cs-137, Ag-110m, U-238, Ra-226 and K-40). Short-lived radionuclides Cs-134 and Ag-110m released from Fukushima NPP Accident were found in the samples, with an extremely high water-to-organism concentration ratio for Ag-110m (> 2.9E + 04). The radiological dose rates for the squid from the radionuclides measured were far lower than the relevant benchmark of 10 µGy h−1. For human consumers ingesting these squid, the dose contribution from natural radionuclides (> 99.9 %) including Po-210, was far greater than that of Fukushima-accident radionuclides (


1981 ◽  
Vol 18 (5-6) ◽  
pp. 987-999 ◽  
Author(s):  
W.L. McLaughlin ◽  
J.C. Humphreys ◽  
H. Levine ◽  
A. Miller ◽  
B.B. Radak ◽  
...  

2020 ◽  
Vol 5 (3) ◽  
Author(s):  
Nessreen Abdelfatah Ali Abdoun

Abstract  This work was carried out with the aim to establish baseline data of soil radioactivity prior commissioning the first nuclear power plant for electricity production in the Sudan. A total of 105 soil samples from the proposed area were collected and analyzed using Gamma-ray spectrometer, X-ray Fluorescence and Atomic Absorption. Ambient dose rates were measured during sampling using radiation survey meters. Based on radionuclides in soil; some radiological hazard indices (such as absorbed dose rates, Radium-Equivalent Activity, External Hazard, and Gamma index) were computed. The results exhibit that226Ra, 232Th,40Kand 137Cs concentration ranged from0.55-88.9, 1.63-76.6, 24-1100 and 0.001-1.03 Bq/kg with an average value of10.43, 11.12, 361.2and 0.045Bq/kg respectively. The average value of absorbed dose rate(29.92nGy/h), Radium equivalent (70.55 Bq/Kg), external hazard (0.19), Gamma index. (0.25) and those parameters are lower than the corresponding global average. The results of the study revealed that the average values of 226Ra, 232Th, 40K and 137Cs fall within the global average value. GIS Predictive exhibited the spatial distribution of radioactivity trends with low levels at eastern part towards the Red Sea while high values observed at the desert (western part). This trend in addition to low levels has a very good impact to decision makers for consideration in site selection of NPP. Pearson correlation coefficient shows a correlation between the variables 226Ra and 232Th (0.69); Cr and Au (0.82); Br and Nb (0.84),Hf and Sb (+0.75) with no significant correlations between radioactive and radioactive elements. Keywords: Road map, GIS, Gamma-ray Spectrometer, Effective dose.  


2014 ◽  
Vol 68 (4) ◽  
pp. 449-455 ◽  
Author(s):  
Ljiljana Jankovic-Mandic ◽  
Ranko Dragovic ◽  
Milan Djordjevic ◽  
Maja Djolic ◽  
Antonije Onjia ◽  
...  

Among radionuclides in the soil deposited after Chernobyl accident, 137Cs poses considerable environmental and radiological problems because of its relatively long half-life (30.17 y), its abundance in the fallout, high mobility and similarity to potassium as the major plant nutrient. In this study the samples of undisturbed surface soil (n=250) were taken from 70 regions in Belgrade, during 2006-2010. The specific activities of 137Cs were measured by gamma-ray spectrometry. Based on obtained results external effective dose rates were calculated according to the internationally accepted activity to dose rate conversion equations. The specific activities of 137Cs were geographically mapped. The presence of 137Cs has been detected in all soil samples, with high variability of its specific activity, ranging from 3 Bq kg-1 to 87 Bq kg-1. The mean specific activity of 137Cs was 23 Bq kg-1 and the corresponding absorbed dose was 1.5 nSv h-1. The observed range reflects the inhomogeneity of the deposition process following the Chernobyl accident. It could also be attributed to topographic differences and spatial differences in physicochemical and biological soil properties, soil type and vegetation cover. The results of the present study could be valuable database for future estimations of the impact of radioactive pollution.


Author(s):  
Francesco Caridi ◽  
Giuseppe Paladini ◽  
Valentina Venuti ◽  
Vincenza Crupi ◽  
Salvatore Procopio ◽  
...  

In the present article, a case study is reported regarding an investigation carried out in order to assess radioactivity concentration, heavy metals pollution and mineralogy of a beach stretch extending from Soverato to Squillace municipalities of the Ionian coast of Calabria, South of Italy, a popular tourist destination, especially in summer. The analysis of radionuclides contents was performed by using a High Purity Germanium (HPGe) gamma-ray detector, in order to quantify the average specific activity of 226Ra, 232Th and 40K natural radionuclides and 137Cs anthropogenic radioisotope. The absorbed dose rate and the annual effective dose equivalent radiological hazard indices were also estimated. Furthermore, X-ray Fluorescence (XRF) spectrometry measurements were carried out for the quantitative elemental analysis of the sand, in order to investigate any possible chemical pollution by heavy metals. For this aim, different indices such as Enrichment Factor (EF), Geoaccumulation Index (Igeo), Contamination Factor (CF) and Pollution Load Index (PLI) were applied to estimate the level of toxicity imposed on the ecosystem by the detected heavy metals. Finally, in order to identify the crystalline mineral components of the investigated sand samples, X-ray Diffraction (XRD) and Micro-Raman Scattering (MRS) measurements were carried out.


Sign in / Sign up

Export Citation Format

Share Document