scholarly journals Distribution and Characteristics of Radon Gas in Soil from a High-Background-Radiation City in China

2011 ◽  
Vol 48 (5) ◽  
pp. 751-758 ◽  
Author(s):  
Nanping WANG ◽  
Lei XIAO ◽  
Canping LI ◽  
Shaomin LIU ◽  
Ying HUANG ◽  
...  
2019 ◽  
Vol 7 (2) ◽  
pp. 57-60
Author(s):  
Amir Mehdizadeh ◽  
Sedigheh Sina ◽  
Reza Faghihi ◽  
Mohammad Hosein Sadeghi

Background: Radium-226 is a radioactive element, with a very long half-life of 1600 years, producing radon gas. According to the United States Environmental Protection Agency, radon gas is the second most important factor causing lung cancer. Objectives: The purpose of this study was to separate 226Ra from the soil of high background radiation area by a radiochemical method for using in radon calibration chamber. Methods: 226Ra can be used in standard calibration chambers for calibration of radon detection systems. For this purpose, radiochemical method was used to extract radium from the soil with a high concentration of 226Ra. Four soil samples used in this study were selected from high background radiation areas of Ramsar, north of Iran. Equal amounts of samples were gathered from each region and ground. The specific activity of radium-226 was measured with HPGe detector. The highest specific activity of radium-226 (44.8 Bq/g) belonged to Talesh-Mahaleh. After radiochemical separation of 226Ra, the specific activity of extracted radium crystals was measured with the HPGe detector. Results: According to the results, the specific activity of 226Ra was found to be 94.97 Bq/g. Therefore, the specific activity of 226Ra was 2.12 times greater in the extracted crystals than in the original soil samples. Conclusion: The results indicate that using the radiochemical method proposed in this study, 226Ra can be extracted with an efficiency of 42%


2020 ◽  
Vol 16 (4) ◽  
pp. 407-414
Author(s):  
Fatemeh Heidari ◽  
Zeinab Shariatmadari ◽  
Hossein Riahi

Background: Microalgae are the source of various compounds with high potentials for being used in different industries. The production of such compounds can be raised under extreme conditions. In the present study, four cyanobacteria and one coccoid green alga were examined which were isolated from hot springs in high background radiation areas in Ramsar, a city in the north of Iran. Methods: Cadmium adsorption from aqueous solution, response towards cadmium stress, antioxidant activity, total phenolic compound and drought tolerance were investigated in these microalgae. Results: The results showed that these extremophile microalgae contain valuable biological compounds which can be useful in remediation of heavy metals from contaminated water and soils and pharmaceutical applications. The unicellular cyanobacterium, Chroococidiopsis thermalis IBRC-M50002, was the best strain with the highest biological activity in various testes such as cadmium adsorption (225 mg g-1), cadmium tolerance stress (100 mg ml-1), antioxidant activity (IC50= 18 μg mg-1) and total phenol content (100 μg ml-1). The coccoid green algae Grasiella emersonii IBRC-M50001, also exhibited significant antioxidant activity (IC50=10 μg mg-1) and total phenol compound (116 μg ml-1), but its cadmium adsorption, tolerance at cadmium stress and desiccation were lower than Chroococidiopsis thermalis. Conclusion: HBRAs microalgae, isolated from extreme conditions, are useful microorganisms for the production of bioactive substances and natural antioxidants. In other words, they exhibited high capacity to be used in pharmaceutical, industrial and commercial applications.


2006 ◽  
Vol 125 (1-4) ◽  
pp. 565-567 ◽  
Author(s):  
C. Sainz ◽  
L. S. Quindos ◽  
P. L. Fernandez ◽  
J. Gomez ◽  
I. Fuente ◽  
...  

2019 ◽  
Vol 184 (3-4) ◽  
pp. 290-293 ◽  
Author(s):  
Darwish Al-Azmi ◽  
Sudeep Kumara ◽  
M P Mohan ◽  
N Karunakara

Abstract Elevated levels of natural background radiation due to scattered patches of monazite sand around the beaches of Mangalore, India, have been reported earlier. A comparative study of gamma dose rates was performed in both normal background and high natural background radiation areas around Mangalore using different types of portable gamma dosimeters. In addition to this, gamma-ray energy spectra were acquired, in situ, using a NaI(Tl) based portable gamma spectrometer. Soil and sand samples were collected for laboratory analysis with HPGe detectors. Measurements were carried out during the years 2016–18 revealed that in majority of the locations the gamma dose rates were similar to the normal background regions, whereas, in certain locations the dose rates were higher with values up to 530 nSv/h.


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